The invention is in the field of suspension systems for the endless tracks of track laying vehicles, more particularly relates to such a suspension system for the drive track of a snowmobile and still more particularly to what is known to the art as a slide rail suspension; however, the system is adaptable as well to a bogey wheel track support arrangement.
During the course of the development of the snowmobile vehicle, the track support element was initially provided with leaf, coil and torsion spring arrangements which were undamped and which due to their mounting and actuating mechanisms provided a rather stiff linear response to displacement of the track, leading to a comparatively rough ride. Later, separate shock absorbers were added usually inefficiently mounted at the rear of the track support frame where their action was not directly associated with the aformentioned spring support elements.
The invention is an improvement in such track suspension systems in that it not only employs matched coaxial spring and shock absorber units, but also includes actuating linkages therefore which provide a connection of variable mechanical advantage with the track support element. The net result is a suspension system that is more forgiving and softer in the early stages of its displacement and yet fully responsive to the more extreme displacement forces encountered in rough terrain and at high speed. Constant track tension through all articulations of the suspension is achieved through the front control arm configuration and angles disclosed.